1006643581 has 2 divisors, whose sum is σ = 1006643582. Its totient is φ = 1006643580.

The previous prime is 1006643567. The next prime is 1006643587. The reversal of 1006643581 is 1853466001.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 787307481 + 219336100 = 28059^2 + 14810^2 .

It is a cyclic number.

It is not a de Polignac number, because 1006643581 - 2⁵ = 1006643549 is a prime.

It is a super-2 number, since 2×1006643581² = 2026662598337007122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1006643587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 503321790 + 503321791.

It is an arithmetic number, because the mean of its divisors is an integer number (503321791).

Almost surely, 2^1006643581 is an apocalyptic number.

It is an amenable number.

1006643581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1006643581 is an equidigital number, since it uses as much as digits as its factorization.

1006643581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 1006643581 is about 31727.6469502546. The cubic root of 1006643581 is about 1002.2096408909.

The spelling of 1006643581 in words is "one billion, six million, six hundred forty-three thousand, five hundred eighty-one".